Jet accelerated missile



Jan. 17, 1961 L. MAAS, JR, ET AL JET AQCELERATED MISSILE Filed May '7,1948 e Sheets-Sheet 1 INVENTORS LEO M445 JR. WAjR/E/V 0. BROWN ATTORNEYJan. 17, 1961 M s, J ETAL 2,968,244

JET ACCELERATED MISSILE 6. Sheets-g 2 Filed May 7' 8 ullilm in. A n. \l/I 4 I null ll 1 WARRE 0 WN ATTORNEY Jan. 17, 1961 1.. MAAs, JR., ETALJET ACCELERATED MISSILE 6 Sheets-Sheet 5 Filed May 7, 1948 N W MW mfim R30. & A O A 2 VMR wk/ 1% Jan. 17, 1961 L. MAAS, JR., EIAL JETACCELERATED MISSILE 6 Sheets-Sheet 4 Filed May '7, 1948 INVENTORS LEOMAAS JR.

WARREN 0. BROWN ATTORNEY 1961 L. MAAS, JR, ETAL 2,968,244

JET ACCELERATED MISSILE Filed May 7, 1948 6 SheetsSheet 5 L0 MAAS JR.WARREN 0. mow/v ATTORNEY 1951 L. MAAS, JR, ETAL- JET ACCELERATED MISSILEFiled May 7, 1948 6 SheetsSheet 6 lmm l INVSHTORS L50 MAAS) JR. WARREN0. BROWN X19 fix ATTORNEY JET ACCELERATED lVIISSILE Leo Maas, Jr., 758S. Ardmore, Los Angeles, Calif., and lqarfien D. Brown, 13420 PembrokeAve., Detroit, ic

Filed May 7, 1948, Ser. No. 25,772

4 Claims. (Cl. 102-49) (Granted under Title 35, US. Code (1952), see.266) This invention relates to an improved jet accelerated armorpiercing projectile, such as a bomb, and more particularly to aprojectile of this type employing novel jet propellant mounting andigniting means.

Conventional armor piercing bombs must ordinarily be dropped from a veryhigh altitude in order to attain a striking velocity sufliciently largeto cause the bomb to penetrate the thick armor of battleships, cementpillboxes, or other armored targets. However, it is well known that athigh altitudes, bombing accuracy decreases because of the high altitudeand because of clouds and bad weather, frequently making it impossibleto see the target from the high altitude at which ordinary bombs must bedropped if their armor piercing qualities are to be efiective. A jetimpulse provides a suitable means for increasing the velocity of bombsdropped at relatively low altitudes. Such a jet impulse is effectivelyproduced by the rapid rearward ejection of gases from a fast burningpropellant powder carried by the bomb.

In a bomb provided with a jet impulse accelerating device, it isnecessary to delay the point of jet initiation in order to assure thatthe bomb is safely clear of the aircraft or other position from which itis launched :before the jet is ignited, and to assure that the jet isinitiated at a point in the normal trajectory of the bomb at which thelateral component of the thrust produced by the jet is at a minimum,thereby increasing the velocity of the bomb with a minimum change in itsnormal trajectory.

It is also desirable in jet accelerated bombs that the increase in sizeof the bomb over an ordinary bomb of equivalent weight be held to aminimum so that the bombs are usable with aircraft having bomb bays ofordinary dimensions. In previously constructed jet accelerated bombs,the jet acceleration means was positioned to the rear of the armorpiercing part of the bomb, resulting in a considerably increased bomblength with the resultant necessity for either increasing the length ofthe bomb bays of aircraft carrying these bombs or reducing the number orsize of the explosive portion of the bombs themselves.

One object of this invention is to provide an improved jet acceleratedbomb or other projectile having a novel arrangement of elements wherebythe length of the bomb is kept at a minimum without substantiallychanging the ballistic characteristics of the bomb.

Another object of the invention is to provide an improved jetaccelerated armor piercing projectile including'novel' means formounting a plurality of tubular rocket propellant grains (commonly knownas rocket motors) about the outer periphery of the armor piercingportion of the bomb.

A further object of the invention is to provide an improved jetaccelerated bomb having a plurality of rocket propulsion motors attachedabout the outer periphery of the armor piercing portion of the bomb andhaving a novel electrical igniting mechanism for initiating action ofthe rocket propellant.

Another. object of the invention is to provide a rocket Patented Jan.17, 1961 accelerated bomb having a plurality of rocket motorssurrounding the outer periphery of the armor piercing portion of theprojectile, means for igniting each rocket motor separately, and meansfor assuring that in case any of said motors is not ignited by saidelectrical means it will be ignited by an adjacent motor.

1 A further object of the invention is to provide means for addingrocket propulsion means to a standard projectile such as a bomb withoutany modification of the projectile itself, thereby simplifyingproduction of the bombs.

A further object of the invention is to provide a rocket propellantigniting device for use with a rocket accelerated projectile whichincludes a simple indicator from which it can be determined whether therocket igniting means is in unarmed condition or has been accidentallyarmed.

A further object of the invention is to provide a jet acceleratedprojectile having aerodynamically operable electrical means forinitiating operation of the jet accelerating means.

A further object of the invention is to provide a jet acceleratedprojectile having an electrical jet ignition mechanism including adeferred action battery for supplying current to ignite the jetpropellant and. a normally open switch interposed between said batteryand the jet propellant. Aerodynamically operated means are provided forinitiating action of the battery and for subsequently closing saidswitch to ignite the jet propellant means.

The above-mentioned and other objects of the invention will be apparentfrom the following specification and the accompanying drawings, in whichFig. l is a longitudinal sectional view of the improved jet acceleratedbomb;

Fig. 2 is a rear elevational view of the bomb;

Fig. 3 is a perspective view of the propellant igniting device in armedcondition with parts of the device broken away for purposes of clarity;

Fig. 4 is an upper end view of the rocket fuze in unarmed condition withpart of the frame member broken away for clarity;

Fig. 5'is a side elevational view of the rocket fuze, partly in section;

Fig. 6 is a side elevational view of the device in unarmed conditionsimilar to Fig. 5 but taken from a different angle;

Fig. 7 is a bottom view of the rocket fuze;

Fig. 8 is a detailed perspective view of the cam follower and latch ofthe fuze;

' Fig. 9 is an end view of the electrical terminal box of the rocketfiring mechanism;

Fig. 10 is a longitudinal sectional view of the electrical terminal boxshown in Fig. 9;

Fig. 11 is a fragmentary detailed cross-sectional view of the manifoldin which the rocket motors are mounted; and

Fig. 12 is a longitudinal sectional view showing the means for mountingthe rocket fuze and the propeller shaft with most of the fuze elementsomitted for clarity.

In the preferred embodiment of the invention as shown in the drawings,the assembly is built around an ordinary 1000 lb. armor piercing bomb 20having a tapered rear portion 20a and having a cavity 21 filled with adetonating explosive charge. A conventional rotatably armed basedetonating fuze 22 is provided for detonating the explosive 21a. Thefuze 22 is screwed into the bomb base plug 23 which is attached to thebomb by conventional means such as threads, and which has a rearwardlyextending hub 24 having screw threads on its outer periphery. A shaft 25(see Fig. 12) is secured to the rotating part 25a of the fuze 22 bymeans of a copper 3 shear wire 22:: and extends rearwardly from the fuze22 for connection to the rotatable shaft of the rocket fuze as will beexplained presently.

A cylindrical metal jacket 27 shorter in length bu larger in diameterthan the bomb 20, and carrying an integral or welded reinforcing ring 28near its forward end is supported on the forward end of bomb 20 by anannular manifold 29 which bears against the ring 28 and is welded to thejacket. At the rear end, the jacket is mounted on the bomb by an annularrear support 31 which is welded to the interior of the jacket 27 nearits rear end. Twelve openings 45 for supporting rocket motors areprovided in the rear support 31. An annular passage 29a in the manifoldserves a purpose which will be described presently.

The rear support 31 bears against the tapered rear end portion 20a ofthe bomb 20, and is maintained in place by the tail support 33 which isannular and of L-shaped cross-section and is adapted to, fit over thethreaded portion of the bomb base plug 23 and to bear against the rearsupport 31. The tail support 33 is maintained in place on the base plugby means of the standard tail lock nut 34. Conventional tail fins 36 arewelded to the tail support 33 to stabilize the flight of the bomb. Acast aluminum ogive 38 is secured to the forward end of the jacket 27 bysuitable means such as screws (not shown). To facilitate handling of theassembled bomb, suspension lugs 40 and hoisting lugs 41 are welded tothe exterior of the casing 27. Trunnions (not shown) may also be weldedto the exterior of the casing in order that the bomb may be used withconventional dive bombing equipment.

The manifold 29 is provided with twelve threaded sockets 29.5 which arealigned with the twelve circular openings 45 in the rear support 31 toreceive an equal number of rocket motors comprising tubular grains ofrocket propellant explosive 47. Each rocket motor is insorted throughone of the openings -45 and is screwed into one of the threaded socketsof the manifold 29. Each motor is provided with a squib 49 located nearits forward end and with an electrical conductor 50 which extendsthrough the hollow interior of the motor from the squib rearwardly andout of the rear end of the motor where it terminates in a plug 51, theutility of which will be described in more detail presently.

The housing 60 of the fuze 22 extends rearwardly from the fuze and has arear portion 61 of narrowed diameter which, when the fuze is used with aconventional bomb not having rocket accelerating means supports anarming vane assembly (not shown) for arming the fuze as the bomb fallsthrough the air. To this narrowed portion is attached the housing 62 ofthe rocket fuze. An electrical junction box 64 shown in detail in Fig.is mounted on housing 60 and is retained in place by means of set screws(not shown) which are. positioned in holes 65 in the narrow rear neckportion of the box. The junction box 64 is preferably of light sheetmetal and is annular, having a central opening through which passes thehousing 60 and the narrow housing portion 61. The forward end of thejunction box rests against the rear end 24 of the bomb base plug 23 andthe lock nut 34. Thirteen electrical sockets 69 are mounted on the rearsurface of the box and extend rearwardly. These sockets are of theconventional two lead type, one lead from each being connected to aninsulated conducting ring 70 positioned inside the junction box and theother lead connected to the insulated ring 71 in the junction box bymeans of short lengths of wire which are housed by the box. A plug 73connected to the rocket fuze is connected to one of the sockets 69 tosupply current to rings 70 and 71 after the rocket fuze is operated,while the other twelve of the sockets 69 are for connection to the plugs51 carried on the ends of wires 50 which are connected to the squibs inthe rocket motors. When all of these connections are made, all of therocket squibs are connected in parallel with the two leads from therocket fuze. In practice, the plugs 51 are usually not plugged into theelectrical junction box until shortly be fore the bomb is to be used,thereby providing an extra safeguard against premature ignition of therocket motors.

The rocket fuze comprises generally a deferred action or reserve'batteryand means for actuating the battery and firing the rocket squibs afterthe bomb has fallen through the air for a predetermined period of time.

More particularly, the fuze is built around a mounting plate 86? mountedby screws (not shown) or other suitable means at the rear end of thecasing 62 for supporting the various elements of the fuze. A cover 62aencloses the rear end of the rocket fuze. A shaft 81 is journaled in theframe member and in bracket ,82 bolted to the frame member, and isconnected by a tongue and groove joint 81a to the rear end of shaft 25.Shaft 25 extends forwardly through suitable bearings 61a in a sleeve 81bwhich is threaded into the narrowed rear end 61 of fuze housing 60 asshown in Fig. 12. The rear end of the shaft 81 carries an armingpropeller 83 which is rotated by the air stream as the bomb fallsthrough the air. The rotation of the propeller 83 serves the dualpurpose of arming the base detonating fuze 22 of the bomb throughrotation of shafts 81 and 25 and of operating the rocket fuze by themechanism shown in detail in Figs. 3 through 7.

Shaft 81 carries an arm 85 which rotatably supports planet gears 86 and87 so as to move the gears 86 and 87 through a circular path around theshaft 81 as the propeller 83 is rotated by flight of the bomb throughthe air after its release. Gear 86 meshes with a fixed sun gear 88 whichis secured to the under surface of bracket 82 coaxially with the shaft81. Gear 87 meshes with a gear 89 which is positively attached to acircular cam plate 90 mounted for rotation on the shaft 81. A gear 91 isfixed to the under surface of the cam plate 90 and serves a purposewhich will be-descri-bed presently.

The fixed gear 88 has one less tooth than the gear 89, and gears 86 and87 have an equal number of teeth so that as the propeller 83 rotates andmoves the planetary gears 86 and 87 through their orbits, the gear 89,cam plate 90 and the gear 91 are rotated slowly, each revolution ofpropeller 83 moving gear 89 a distance equal to one tooth. Assuming thatthe gear 88 has 20 teeth and the gear 89 has 21 teeth, approximately 230revolutions of the propeller 83 are necessary to cause the gear 89 andthe cam plate 90 to make a complete turn.

In order to provide electrical current for firing the rockets, therocket fuze includes a delayed action or reserve battery which is of thetype having a frangible diaphragm or ampule (not shown) which maintainsthe electrolyte separated from the grid compartment (not shown), itbeing necessary to rupture the diaphragm in order to. allow theelectrolyte to flow into the grid compartment to activate the battery.Such batteries are Well known in the art and an example is the one shownin US. Patent 1,658,142. The apparatus for rupturing the diaphragmcomprises a gear 101 which is driven by rotation of the gear 91 andwhich is keyed to one end of a rotatable shaft 102 which carries at itsopposite end a detent 103. In its unarmed position shown in Fig. 4,detent 103 positively retains a plunger 105 out of contact with thebattery 100. The plunger 105 is spring loaded so that after propeller 83has rotated a sufiicient number of times to move the gear 101 and detent103 to their armed positions shown in Fig. 3, the plunger 105 is drivenby its spring into contact with the battery to rupture the batterydiaphragm and allow the electrolyte to flow into the grid compartment,thereby activating the battery. A pointer 108 mounted on the end ofshaft 102 adjacent gear 101 is rotated with the gear 101 to give anindication on the indicator plate 109 of the condition of the fuze. Asuitable window is provided in the fuze casing so that the indicatorplate 109 and pointer 108 are visible from the exterior of the fuze,thus making the condition of the fuze battery apparent to personnelhandling the bomb.

The cam plate 90 has a cam groove 110 in its lower surface, the camgroove being substantially circular in its dwell portion and having anoutwardly extending lobe portion 111 at one end. The cam operated arm112 shown in detail in Fig. 8 carries a cam follower 113 which rides inthe groove 110. The arm 112 is pivotally mounted on the frame member 80and carries a shorter detent arm 114 which normally, that is when thecam follower 113 is in any but the final lobe portion 111 of the camgroove 110, retains a switch member 116 in its open circuit position byits position in the path of switch arm 118.

The switch member 116 comprises a base member 117, a switch arm 118 anda safety arm 118a pivotally mounted on a bracket 119 carried by theframe member 80. A spring 120 anchored at 121 to the frame member 80 isattached to a downwardly projecting ear 124 on the base member 117 andurges the switch arm 118 toward its closed circuit position.

The switch proper denoted generally by the numeral 125 is mounted in asupport 126 attached to the frame member 80. The support 126 carries acontact member 127 which is insulated from the rest of the fuze byinsulation 128 consisting of rubber, fibreboard, or other suitablematerial. When switch arm 118 is freed for movement to its closedcircuit position by the fuze mechanism, the spring 120 rotates theswitch arm 118 into contact with the switch contact 127 to fire therockets.

As a safety precaution against firing of the fuze prior to release ofthe bomb, there are provided a pair of vanes 130 mounted on a shaft 131which is rotatably mounted on the frame member 80. A detent arm 132 isattached to the shaft 131 so as normally to extend into the path of thesafety arm 118a which rotates with switch arm 118. A spring 134 anchoredto the frame member 80 is attached to the detent arm 132 so as to retainthe arm in its detent position until an air velocity of 100 knots isexerted against the vanes 130. As such a large air pressure would not belikely to be exerted upon the vanes until the bomb is launched, thissafety device assures against premature firing of the rockets. A pair ofvane stops 136 are mounted on the fuze frame to limit the movement ofthe vanes 130 under the influence of air pressure.

As a further safety measure, a conventional arming wire (not shown) isused in conjunction with the propeller 83 to present undesired rotationof the propeller. This arming wire is withdrawn from the propeller whenthe bomb is launched.

An insulating electrical terminal plate 140 is attached by a bracket 141to the frame member 80. Attached to mounting posts carried by theterminal plate are a ground wire 142 from the reserve battery 100 andanother lead 143 from the battery. The ground lead 142 is grounded tothe mechanical elements of the fuze through the bracket 141, while lead143 is connected to wire 144 to carry current to conducting ring 70 ofthe terminal box 64. Wire 144 passes through the metallic protectiveshield 146 which is connected to the junction box 64 by plug 69. Lead147 which is connected to metallic ring 71 of the terminal box 64 passesthrough the shield 146 and is attached to a post on the terminal plate140, the post also being connected to the switch contact 127 by means ofwire 148. When the rocket squibs are attached by wires 50 and plugs 51to the junction box 64, all that is necessary after the energizing ofthe battery 100 is the release of switch arm 118 for movement intocontact with the switch contact 127, thereby connecting the rocketsquibs to ground to fire the rockets.

The operation of the device is as follows: When the bomb is loaded intothe aircraft, the propeller 83 is retained against rotation by means ofa conventional arm- '6 ing wire (not shown). The arming wire is removedfrom .the propeller when the bomb is released, thus permitting rotationof the propeller by the air stream as the bomb falls through the air.

The rotation of the propeller 83 first arms the base detonating fuze 22of the bomb through rotation of shafts 81 and 25 so that the basedetonating fuze is armed after the bomb has fallen a predetermineddistance through the air. The copper shear wire 22a which attaches shaft25 to the rotating part of base fuze 22 is sheared after the base fuzeis armed and the rotating parts freeze, thereby assuring that propeller83 and shaft 81 are free to continue their rotation and operate therocket fuze.

Rotation of the propeller actuates the rocket fuze in the followingmanner: when the bomb is released, detent arm 103 is in its retainingposition as shown in Fig. 4 in which it positively retains the plunger105 separated from the deferred action battery 100. Pointer 108 pointsto Safe to indicate that the battery and fuze are unarmed. The switcharm 118 is positively retained in its open position by means of detent114 operable by the cam plate 90, and is further secured in its opencircuit position by detent arm 132 which cooperates with safety arm 118aof the switch.

After the bomb is dropped from the aircraft, the vanes 130 areimmediately moved against the vane stops 136 since the velocity of thebomb is over knots. In so moving, the vanes safety arm rotate shaft 131and move the detent arm 132 out of the path of switch 118a, and sincethe bomb is falling through the air, the detent 132 remains in the armedposition. Rotation of the propeller 83 rotates the planetary gears 86and 87 around the shaft 81 and due to the difference in the number ofteeth in gears 88 and 89, the gear 89 with the attached cam plate 90 andgear 91 is slowly rotated. When the gear 91 has rotated far enough tomove the gear 101 to the armed position as shown in Fig. 3, the detentarm 103 is moved out of the path of the plunger 105 which is then drivenagainst the battery 100 by its spring, thereby fracturing the diaphragmof the battery and permitting the electrolyte of the battery to flowinto the battery grid compartment and activate the battery.

As the propeller 83 continues to rotate, the gear 89 and cam plate 90continue rotating slowly until, after a total of approximately 230revolutions of the propeller, the lobe 111 of the cam groove moves thecam follower 113 outwardly away from the central shaft 81 and therebyremoves the detent 114 from the path of the switch arm 118. As soon asthis occurs, the spring moves the switch arm 118 into contact with theswitch contact 127 to ground the wire 147 connected to the rocket squibsand thereby fire the rockets. In case any rocket fails to fireelectrically, the hot gases from an adjacent rocket ignite the unfiredrocket through the annular passageway 29a in manifold 29. The manifoldalso aids equalization of pressure of the rocket thrust to give a moreuniform thrust and more normal trajectory.

In assembling the bomb, the ordinary 1000 lb. AP bomb 20 is placedupright, nose downward, in a metal base, and the jacket assembly 27including manifold 29 and rear support 31 is slipped over the tail endof the bomb. The tail fin assembly 33, 36 is then placed in position andthe tail lock nut 34 secured. The rocket motors 47 are then slid intothe openings 45 in the rear support 31 and are screwed into the manifold29. The base detonating fuze 22 is then screwed into the bomb base plug23, and the electrical junction box 64 and the rocket fuze 62 areattached to the cover 64 of the base detonating fuze. The assembled bombis then lifted from its supporting base and laid on its side, afterwhich the ogive 38 is slipped in place and secured by screws (notshown). When ready for firing, the plugs 51 are plugged into the matingsockets 69 on the junction box 64.

Due to the great space savings brought about by assembly of the rocketmotors about the body of the bomb want 7 rather than at the rearthereof, the rocket bomb is easily carried in conventional bomb bays andreleased by conventional bomb releasing equipment.

It is to be understood that the rocket fuze may be arranged so that therocket action is initiated at any desired point in the trajectory of thebomb. If desired, the rocket fuze may be used on other types ofprojectiles in which it is desired to delay the ignition of thepropellant for a predetermined period of time after launching.

Although one specific embodiment of the invention has been described andshown in the drawings, the invention is not to be construed as limitedto that embodiment. The various features of the device may assumevarious other forms without departing from the scope of the invention asdefined by the appended'claims.

The invention herein described may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout-the payment of any royalties thereon or therefor.

We claim: I

1. A rocket accelerated missile comprising a projectile having a taperedrear portion, a base plug mounted in the rear end' of said projectileand having a rearwardly extending threaded boss, a casing surroundingsaid projectile, an annular forward spacing member mounted on theinterior of said casing, a rear spacing member fixed to said casing andhaving a rearwardly flanged central opening adapted to fit tightly onsaid tapered portion of the projectile, a plurality of rocket motorsmounted between said projectile and said casing and supported by saidhaving an armor piercing nose portion, detonating means for saidexplosive contained in the base portion of said projectile, a pluralityof elongated rockets mounted peripherally of said projectile and havingtheir longitudinal axes generally paralleling the axis of saidprojectile, separate electrically operated ignition means for each ofsaid rockets positioned at the end thereof adjacent said nose portion;means for producing electrical energy for said ignition means, adistributor connector positioned adjacent the base of said projectileand concentric with said detonating means, for connecting each of saidelectrical operated ignition means in parallel, and a switch forconnecting said electrical energy produced by said means to saiddistributor.

3. The combination defined in claim 2 characterized further by theaddition thereto of aerodynamically operated means for rendering activesaid electrical energy producing means, for operating said switch andfor arming said detonating means.

4. The combination defined in claim 2 characterized further by theaddition thereto of a manifolding means for communicating each of saidrockets at said end whereby to equalize the pressure in said rocket andto provide alternate, ignition means for an individual rocket in theevent of failure of its individual electrically operated ignition means.

References Cited in the file of this patent UNITED STATES PATENTS2,332,670 Rouse Oct. 26, 1943 2,403,567 Wales July 9, 1946 2,404,553Wales July 23, 1946 FOREIGN PATENTS 347 Great Britain Jan. 26, 1878831,496 France June 7, 1938 568,542 Great Britain Apr. 10, 1945

